Building structure



FIG. 1 is a perspective view of a building structure showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a right elevational view thereof;

FIG. 4 is a left elevational view thereof; and

FIG. 5 is a rear elevational view thereof. 

The ornamental design for a building structure, as shown and described. 